Power on - sometimes the system boots and runs for 30 odd mins. then freezes. Sometimes boots and runs for a few minutes or even seconds before freezing, sometimes does not boot to BIOS, freezes whilest in BIOS. In short - it can freeze at anytime during the boot process.

Looks like overheating - supplied fan works fine, used a fan for Athlon 6000+ x2 - bigger but no difference.

When I have been able to access BIOS have noted that MINIMUM Voltage for memory is 1.9V!! Specs say 1.8V though BIOS will not allow this value. Specs. for Elixir Memory say they should run at 1.8V. Could this be the cause?

"When I have been able to access BIOS have noted that MINIMUM Voltage for memory is 1.9V!! Specs say 1.8V though BIOS will not allow this value. Specs. for Elixir Memory say they should run at 1.8V. Could this be the cause?"

Have 2 x CDs, floppy and SataII disk. It's an oldish ATX box with 20 pin power connector, using this in the boards 24 pin power connector socket(aligned with pins 1, 13) plus the 12V 2x2-pin power connector for CPU.

Will do the memory test - assuming the box will stay up long enough for me to do so.Cheers.

Ditto, the power supply would be the first thing I would suspect as the problem. If you have to replace the power supply consider spending a little extra to get one that you can use in future builds and/or hardware upgrades. IMO, there is no such thing as overkill as far as a "more than you need" power supply is concerned!

Did the sums - PSU is underpowered (junk was a fair description .. ). So after a bit of reading have sided with the single rail and future proofing arguments.

Have installed a Corsair TX750W (only £15 more than the 650W) and system fails to boot ... does not reach BIOS. At this stage I suspect that there is no power to the CPU.

Power is getting through to the board via the 24-pin ATX power connector - all fans, peripherals power up.

CPU power (is) provided by the detachable 4-pin connector from the 8-pin EPS12V connector (whatever that is) - am using the correct 4-pin (I hope) "P4/12v" (this has two square and two semi-circular 'pins' that match up to the motherboard 4-pin socket). Its the only socket from the PSU which will fit.

With regards to overheating - am using an AMD x2 5400 with the fan from the AMD x2 6000+ so should not be a problem, should certainly be able to boot into BIOS and POST etc..

If the cabling from the PSU is correct .. then I'm wandering if I have damaged the motherboard.

When I first installed the AMD x2 6000+ (I was very, very *&^$% sloppy) and damaged/bent some of the CPU pins - the system still booted and ran albeit not to design - now there's a suprise! i.e. system booted with incorrectly seated CPU. I checked the CPU, realised what a balls up I'd made, straightened out and realigned all the damaged pins and reseated the CPU correctly. Installed Linux. Linux started misbehaving in ways that I know are NOT down to the software along with the 'freezes' that I have described earlier. So I assumed that I had damaged the CPU and replaced it with a x2 5400. This I have installed properly.

So now - CPU is not damaged, PSU is new, powerful enough and a good one, all cards checked and reseated, connections to peripherals double, triple, ... checked. All I can think of is power to CPU?, motherboard? or something really obvious that I have overlooked!! or something really stupid that I have done.

Done as suggested - it's back up. Plugged in PC speaker so could use the beep codes on POST. One of the memory modules is kaput. I know this was suggested earlier and although system was never up long enough to run a full memory test I did swap them out, try singularly etc.. - must have used the dodgy module twice, thought it would be something stupid!!

Done as suggested - it's back up. Plugged in PC speaker so could use the beep codes on POST. One of the memory modules is kaput. I know this was suggested earlier and although system was never up long enough to run a full memory test I did swap them out, try singularly etc.. - must have used the dodgy module twice, thought it would be something stupid!!

PSU was still an issue.

Thanks for all suggestions.

"One of the memory modules is kaput. "

No any wonder, memory "Elixir" is piece of crap. {Very high RMA rate}

"PSU was still an issue."

Yes, good that you have change it too. Congrats for the excellent PSU choice as well It will serve you very well

"Done as suggested - it's back up. Plugged in PC speaker so could use the beep codes on POST. I know this was suggested earlier and although system was never up long enough to run a full memory test I did swap them out, try singularly etc.. - must have used the dodgy module twice, thought it would be something stupid!! Thanks for all suggestions."